diff --git a/indra/newview/installers/windows_x64/firestorm.wxs b/indra/newview/installers/windows_x64/firestorm.wxs
index fc630ad731..1220463c0c 100644
--- a/indra/newview/installers/windows_x64/firestorm.wxs
+++ b/indra/newview/installers/windows_x64/firestorm.wxs
@@ -8,8 +8,8 @@
   <Package InstallerVersion="200" Compressed="yes" Platform="x64"/>
   <MajorUpgrade DowngradeErrorMessage="A later version of [ProductName] is already installed. Setup will now exit." MigrateFeatures="no"/>
   <Icon Id="firestorm.ico" SourceFile="$(var.WIX_SOURCEDIR)\..\windows\firestorm_icon.ico"/>
-  <Property Id="MSIFASTINSTALL" Value="1"/>
-  <Property Id="ARPSIZE" Value="204800"/>
+  <Property Id="MSIFASTINSTALL" Value="4"/>
+  <Property Id="ARPSIZE" Value="256000"/>
   <Property Id="ARPURLINFOABOUT" Value="http://www.firestormviewer.org"/>
   <Property Id="ARPURLUPDATEINFO" Value="http://www.firestormviewer.org/downloads/"/>
   <Property Id="ARPHELPLINK" Value="http://www.firestormviewer.org/support/"/>
@@ -17,13 +17,13 @@
   <Media Id="1" Cabinet="firestorm.cab" EmbedCab="yes" CompressionLevel="high"/>
 
   <!-- VersionNT64 is undefined if the operating system is not 64-bit: http://msdn.microsoft.com/en-us/library/aa372497%28v=vs.85%29.aspx -->
-  <Condition Message="You can't install Firestorm viewer in 64 bit version on computer without support for the 64 bit architecture. Installation canceled.">
+  <Condition Message="Installing the 64 bit version of Firestorm viewer on a 32 bit Operating System is not supported. Installation canceled.">
     <![CDATA[VersionNT64]]>
   </Condition>
 
-  <!-- OS list: http://msdn.microsoft.com/library/aa370556.aspx - WinXP_x64 is based on Windows Server 2003 -->
-  <Condition Message="Firestorm viewer in 64 bit version is only supported by Windows XP Professional x64 SP2, or newer. Installation canceled.">
-    <![CDATA[Installed OR (VersionNT64 > 502) OR (VersionNT64 = 502 AND ServicePackLevel >= 2)]]>
+  <!-- OS list: http://msdn.microsoft.com/library/aa370556.aspx -->
+  <Condition Message="Your system does not meet the minimum requirement of Vista x64 with Service Pack 2 or newer. Installation canceled.">
+    <![CDATA[Installed OR (VersionNT64 >= 601) OR (VersionNT64 = 600 AND ServicePackLevel = 2)]]>
   </Condition>
 
   <Directory Id="TARGETDIR" Name="SourceDir">
diff --git a/indra/newview/installers/windows_x64/installer.wxs b/indra/newview/installers/windows_x64/installer.wxs
index dc8893b9f8..930b0e3eac 100644
--- a/indra/newview/installers/windows_x64/installer.wxs
+++ b/indra/newview/installers/windows_x64/installer.wxs
@@ -8,7 +8,7 @@
 		  HelpUrl="http://www.firestormviewer.org" 
 		  AboutUrl="http://www.firestormviewer.org" 
 		  Copyright="Copyright© 2014, Phoenix Firestorm Project Inc" 
-		  Condition="VersionNT >= v6.0"
+		  Condition="(VersionNT = v6.0 AND ServicePackLevel = 2) OR (VersionNT >= v6.1)"
 		  IconSourceFile="$(var.WIX_SOURCEDIR)\..\windows\firestorm_icon.ico"
 		  >